No they don't : neither as active current banners nor as finished banners.

I use the core banner system.

I use XOOPS 2.0.17 (and protector 3.02)

Banner display was activated. 3 banners were active (banners of mine, not really advertisement).
A user told me that other banners (advertisement for emule for instance) appear in the banner place. He sent me a screen shot.
I de-activated banner display, and all banners (mines and the other ones) have disappeared.

What is happening?
How can I get rid of these "clandestine" banners ??
does it imply some external code gets mixed with my site code ??!

Thank you in advance for any help.